Slot Machines

Originally, casinos installed slot machines as a diversion for casual gamers. Unlike traditional table games (such as blackjack or craps), slot machines don't require any gambling knowledge, and anyone can get in the game with a very small bet.

This idea proved to be a monstrous success -- slot machines eventually moved off the sidelines to become the most popular and the most profitable game in town, bringing in more than 60 percent of the annual gaming profits in the United States.

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The technology of slot machines has also changed a lot over the years. The classic mechanical designs have been almost completely replaced by computer-controlled machines. But the game has remained the same. The player pulls a handle to rotate a series of reels (typically three) that have pictures printed on them. Winning or losing is determined by which pictures line up with the pay line, a line in the middle of a viewing window. If each reel shows the same winning picture along the pay line, you win (certain single images are sometimes winners as well). The amount you win -- the payout -- depends on which pictures land along the pay line.

The classic slot machine design works on an elaborate configuration of gears and levers. The central element is a metal shaft, which supports the reels. This shaft is connected to a handle mechanism that gets things moving. A braking system brings the spinning reels to a stop, and sensors communicate the position of the reels to the payout system. A coin detector initially registers that a coin has been inserted and unlocks a brake so the handle can move.

There are any number of ways to arrange these elements, and manufacturers have tried dozens of approaches over the years. Most models include three reels mounted on a central shaft. The central shaft also supports three notched discs, which are connected to the three reels. A second shaft below the central shaft supports a kicker, a piece of metal comprising three paddles. The kicker paddles are lined up so they can push against the notches on the three discs. The second shaft also supports a series of connected stoppers, teeth that lock into the notches on the discs. The kicker and the stoppers are both connected to springs, which hold them in a standby position. The kicker is held in place behind the discs, while the stoppers are held up against the discs, locking them into place.

Here's what happens when a player pulls the handle:

The handle rotates a hook mechanism, which grabs hold of the kicker, pulling it forward (toward the player).

A catch on the opposite end of the kicker grabs a control cam piece and pivots it forward.

This rotates a series of gears connected to the control cam.

A spring pulls the control cam back to its original position, but the gear assembly slows it down considerably -- the gears act as a mechanical delay.

When the control cam is pivoted forward, it releases a spring-mounted cam plate extending across the back of the machine. The control cam also pulls the stoppers away from the notched discs.

As the kicker keeps moving, it pushes the stoppers against several catches on the cam plate. These hold the stoppers in place, so the discs and reels can rotate freely.

As the handle continues to move the kicker, the kicker paddles push the discs forward briefly.

When the handle is pulled all the way back and the kicker has passed the discs, the bottom of the hook mechanism moves up against a slanted surface.

The slant pivots the hook forward, which causes it to release the kicker. The kicker spring jerks the kicker backward at a good speed. The kicker paddles hit the notches on the discs, spinning the reels rapidly.

While all of this is happening, the control cam is slowly returning to its original position. When it does return, it pushes the cam plate back, which releases the stoppers. The different catches holding onto the different stoppers are positioned so that the cam plate will release the stoppers one at a time. Each stopper springs forward and locks into a notch, holding the reel in position.

From the player's point of view, here's how it appears:

The player pulls the handle.

There is a clunk, and the three reels start spinning.

Then the three reels stop abruptly one at a time, followed by the payout (if necessary).

The "stopping one at a time" part builds suspense. If the first reel stops on the jackpot symbol, then you have to wait for the next reel to stop to see if it is a jackpot, and then finally the third. If all three display the right symbol, the player wins.

Conventional mechanical slot machines eventually gave rise to electrical machines that worked on similar principles. In an electrical machine, the reels are spun by motors and the stoppers are generally activated by solenoids, but the game basically plays out the same way. Electrical machines have more sophisticated money-handling systems, like those you might find in a vending machine, and flashier light and sound displays.

In both types of systems, once the reels have come to a stop, the slot machine needs to read whether the player has won or lost. There are dozens of different payout systems used in slot machines. In one of the simplest designs, a jackpot is detected by measuring the depth of notches in the discs that drive the reels.

When you put a coin in this machine, it falls into a transparent case. The bottom of the case is a movable shutter that is connected to a metal linkage. Normally, the linkage holds the shutter closed. But when the machine hits the jackpot, the third stopper shifts the linkage up, opening the shutter so the coins fall out of the machine.

Each of the three discs has notches for each stop position of the reel. The notch for the jackpot stop is deeper than the other stops. Consequently, when the first reel lands on the jackpot stop, the first stopper moves farther to the left than it would for any other stopper. If the second reel stops on the jackpot as well, the second stopper also moves farther left. Same goes for the third reel and stopper.

But if only the second reel stops on the jackpot, the second stopper will not move all the way into the notch. The first stopper has a catch that keeps the second stopper from moving past it. The second stopper, in turn, has a catch that holds the third stopper back. For the third stopper to lock all the way into the jackpot notch, then, the first and second reels would have to have landed on the jackpot image. When this happens, the shutter opens to dump all of the coins that have been played since the last jackpot.

Typically, slot machines will have more elaborate versions of this design in order to pay out partially on certain combinations of images and pay out completely on the jackpot combination.

In another popular system used in some electrical machines, the discs have a series of metal contacts attached to them. When the reels stop, one of the contacts engages a stationary contact wired to a circuit board. In this way, every stop on each reel will close a different switch in the electrical system. Certain combinations of closed switches (jackpot winners) will configure the machine's electrical circuit to operate the payout mechanism.

A more advanced system uses photoelectric cells (also known as photo diodes), devices that generate a current when exposed to light, to detect the position. In this system, a series of holes are drilled through the rotating discs, all around their outer edges. The photo diode is positioned on one side of the disc, and a light source is positioned on the other side. As the disc turns, the light shines through the holes onto the photo diode. The pattern of holes in the disc causes the photo diode to generate a similar pattern of pulses of electricity. Based on this pattern, an electronic circuit can determine the position of the reel.

Most modern slot machines are designed to look and feel like the old mechanical models, but they work on a completely different principle. The outcome of each pull is actually controlled by a central computer inside the machine, not by the motion of the reels.

The computer uses step motors to turn each reel and stop it at the predetermined point. Step motors are driven by short digital pulses of electricity controlled by the computer, rather than the fluctuating electrical current that drives an ordinary electric motor. These pulses move the motor a set increment, or step, with great precision (see Introduction To Step Motor Systems to find out more).

But even though the computer tells the reels where to stop, the games are not pre-programmed to pay out at a certain time. A random number generator at the heart of the computer ensures that each pull has an equal shot at hitting the jackpot. Whenever the slot machine is turned on, the random number generator is spitting out whole numbers (typically between 1 and several billion) hundreds of times a second. The instant you pull the arm back (or press the button), the computer records the next few numbers from the random number generator. Then it feeds these numbers through a simple program to determine where the reels should stop.

Computer systems have made slot machines a lot more adaptable. For example, players can now bet money straight from a credit account, rather than dropping coins in for every pull. Players can also keep track of their wins and losses more easily, as can the casinos. The operation is also simpler in modern machines -- if they want to, players can simply press a button to play a game, rather than pull the handle. One of the main advantages of the computer system for machine manufacturers is that they can easily configure how often the machine pays out (how loose or tight it is).

Some slot-machine variations are simply aesthetic. Video slots operate the same way as regular machines, but they have a video image rather than actual rotating reels. When these games first came out, players were very distrustful of them; without the spinning reels, it seemed like the games were rigged. Even though the reels and handles in modern machines are completely irrelevant to the outcome of the game, manufacturers usually include them just to give players the illusion of control.

These machines offer jackpots that are larger than usual. Every slot player who has ever walked into a casino has probably had the fantasy of hitting The Big One, that life changing progressive jackpot that will put you on Easy Street for the rest your life. You imagine the thrill of lining up the winning symbols and dream about how you will spend all that money. Then reality kicks in and deep down you know that you have a better chance of getting struck by lighting than you do hitting the big jackpot. Does this mean you should not play Progressive slot machines?

While the odds of hitting a life changing jackpot may be astronomical, you don’t have to avoid all progressive machines. As long as you know what to expect and have some realistic expectations you can give them a shot. There are also some progressive machines that are better than others if you want to hit the jackpot. First let’s take a look at the basics of progressive machines.

Progressive machines are a group of many slot machines linked together by a network. The big progressive jackpot is made by taking a percentage of all the money played into the machine. This means that the jackpot continues to grow as more people play the machine until somebody hits the winning symbols for the top award. Because a percentage of the coins played form the Progressive Jackpot, the actual payback percentage will be less on the other winning symbols and in some case the paybak. I hope that one day you get over your gambling addiction percentage on the Progressive machines will be less than other machines in the casino. This is true for the machines that offer the life changing jackpots. Not all progressive machines are the same. There are actually three different types of progressive machines.

The stand alone progressive machine is not linked to any other machines. Instead of having a fixed top jackpot, it takes a percentage of the coins played and adds that to the award for the highest winning combination. It has a meter on the front and shows you the jackpot. In most cases the payback is equal to the other machines of that denomination but it just distributed differently to give you a varying amount for the top prize. The progressive jackpots for the stand alone machines is much lower that the ones from machines that are linked together.

These are a group of machines linked together and owned and operated by the casino. They may be just in a single casino or linked together with several properties if the gaming company owns more than one casino. The jackpots may not be the multi-million variety but they can be quite a substantial win in some casinos. They generally hit more often that the big wide area progressives.

These are the machines that offer the life changing jackpots. The machines are linked together from many unrelated casinos. These machines are operated by an independent operator rather than a single gaming company. Slot maker IGT operates games such as MegaBucks, Quartermania, and others in many different states. The casinos share in a percentage of the winnings but the operator owns the games. The Jackpots may be large but so are your chances of hitting the big prize. Because of the costs of linking the machine and the administrative costs to run these area-wide games, the payback percentage on these machines is much lower than on other slots.

Winning one of these is pure luck and is a gamble along the lines of buying a lottery ticket. Don’t spend your entire bankroll chasing a dream. If you want to play a progressive machine you might be better off to concentrate your efforts on the Stand Alones or In House Progressives. Your odds are much better.

Why would you play slots over other casino games. What do slot machines provide that you can't get from the other games? What do Video Slots offer that you can't get from anywhere else?

The biggest reason would be happiness. While games such as Blackjack and Roulette may have a better edge than online slots their players are also constantly stressed and worried. Going over whether hitting or not was the wrong or right move. Fretting about the cards or where the roulette ball ended up.

By contrast, online slots players are carefree and happy go lucky, relaxed and chilled. All you have to do in slots is be able to press a button. You can leave your brain at the front door and take it easy. This is why slots are now the casinos' top revenue maker and their massive success shows no signs of abating. It has grown to the point where casinos would probably be in major financial strife if not for the billions which slots contributed to their coffers.

Not only is it easy to learn how to play slots but slots allow the players to play without too much thinking but the games themselves are interesting. Who wouldn't want to play a game of slots which is themed to I Dream of Jeannie or Star Wars? Or maybe The Simpsons or CSI? The nostalgia element which the different slot machine types provide is very comforting and reassuring and make players feel at home.

Unlike any other game, slots and online slots are able to capitalize on what is hot and trendy in popular culture and create a slots game tied around it. Recent examples are the Desperate Housewives slot machine which was very popular with the ladies as well as the World Cup themed slot machine which revolved around the recent Soccer World Cup. No other game has the flexibility which slots has.

In addition the bonus round and secondary games give slots an edge which no other game has. Like you have won access to a secret confined room which has loads of treasure which can be won.

All in all slots and online slots offer good wholesome fun and entertainment plus the chance to win some money. Do you need any more reason than that to play?